<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>do...while...</title>
</head>
<body>
    
</body>
</html>

<script>
    // let id = 2;
    // do{
    //     console.log(id)
    // }while(--id > 0);


    function yanghui(row){
        row = row || 1;
        let start = 0;
        do {
            let n = 0;
            do {
                document.write('*');
            } while (++n <= start);
            document.write('<hr/>')
        } while (++start <= row);
    }
  
  yanghui(100)
</script>